Selective signaling system



May 14, 1929. F. A. BENNETT I SELECTIVE SIGNALING SYSTEM Filed Aug. 29, 1927 Z ShGetS-Sheet 2 I 15.4. 27 5a 58 FF 1 2a es u z PIE. 5. 27 5% .56

I ATTORNEYS.

Patented May 14, 1929.

FRED A. BENNETT, F CHICO, CALIFORNIA.

SELECTIVE SIGNALING SYSTEM.

Application filed August 29, 1927. Serial No. 216,019.

This invention relates generally to electrical systems in which one station may signal selectively to any one of a plurality of receiving stations. The invention is particularly designed for use in telephone systems in which a plurality of telephone subscribers are connected to a common or party line.

It is an object of this invention. to devise a selective signaling system which will. operate 10 with a simple impulse code and which will utilize energy transmitted "from the central or selecting station for eifecting the desired signal. response at one of the receiving stations.

It is a further object of this invention to devise a selective signaling system especially adapted for ringing the bells of subscribers of party telephone lines, which will require no special apparatus for the central ringing station, and which will notnecessitate batteries or other sources of energy at each of the subscribers stations.

It is a further object of this intention to devise a mechanism which may be readily incorporated with standard telephone systems so as to function to automatically connect the ringer of the telephone to the line in response to a particular combination of impulses.

Further objects of this invention will appear from the following description in which if have set forth the preferred embodin'ient of my invention. It is to be UHdQlSJOUKl that the appended clai is are to be accorded. a range of equivaleius consistent with the state of the prior art.

Referring to the drawing:

Fl 1 is side elevational view illustrating diagrammatically the essenial parts of tie apparatus of this invention.

Figs. 2. l and F are similar to Fig. 1.. but illustrate dillerent operative positions of the selecting mechanism.

Fig. 3 illustrates the different code signals utilized for selectively signaling to a plural.- ity of stations.

Fig. 6 is a circuit diagram illustrating the manner in which the apparatus shown in l igs. 1., 2., i and 5 maybe incorporated with a standard telephone system.

The invention may be outlined briefly as comprising a pair of switches which are ada11 ted to be automatically closed to operatively connect the ringing magnets of a telephone to the telephone line, after a certain code has been transmitted from the central station. The selecting mechanism includes a selecting magnet adapted to be permanently connected to the telephone line, and which is actuated upon the reception of each selector impulse to rotate a selector wheel. After a predetermined number of selecting impulses have been received, the selective wheel has been moved to a position in which it causes closing of the contacts of one of the ringer switches. The contacts of the other switch are adapted to remain open during the reception of selector impulses, but s adapted to close during the reception of a following long ringing impulse, and a portion of this ringing impulse is therefore caused to pass thru the telephone ringing magnets. At the end of the long ringing impulse, means is provided whereby the selector wheel is returned to initial position in readincss for a new signal code. From the fore going it is clear that to effect a response at one particular station a certain ni'inihcr of selecting impulses are transn'iitted, followed by a relatively long signal or ringing impulse, and that to distinguish or select different stations a different number of selecting impulses are utilized. 1

In the drawing 1 have not attempted to disclose a commercial type of apparatus, but have merely indicated the general character of the dilferent mechanical. parts so that one skilled in the art may readily construct the 8211110. The fundamental principles of the invention may be understood more readily by first referring to the circuit diagram of Fig. 6. In this diagram the lines L and L represeut the usual subscribers lines which lead from. a telephone central and which are connected to a plurality of telephone sul scribers A and B. In the ordinary telephone equip ment each subscriber is prov ded with a suitable maguetic ringer l0 coimected across the lines L and L in series with a ringing condenser 11. In. this invention switches 12 and 13 are inserted in series with the ring r so that both switches must be closed he or pulsating ringing impulse will effect an audible signal.

The apparatus shown in lligs. 1, 2, l and 5 is for the purpose of effecting automatic closin of switches 12 an d 13 in re sponse to the reception of a certain nuu'iber of selecting impulses. The motive element for each selective mechanism consists of the selector magnets 14L which are generally permanently connected across the lines L and L. in series with the condenser 11.

Referring now to Fig. 1 for a detail description of tho selecting mechanism, the selecting mangnets 24 are shown as provided \Vllih an armature 26 biased as by means of gravity to open position and adapted to reciprocate a member 2'7, which member is connected to the arn'iature 26 thrua suitable lever 28. Also pivotally connected to the lever 28 is a pawl 29 which is adapted to engage a toothed wheel 31 pivotally mounted upon shaft 32. Rotation oit ratchet wheel. 31 is adapted to carry with it a selector wheel and both ratchet wheel 31 and selector wheel 33 are biased to rotate in a cloclnvisedirection by suitable means such as a spring A projection 36 on the notched wheel 31 is adapted to engage a fixed member 37 and thereby limit rotation of the selector wheel.

The switch corresponding to switch 12 in the circuit diagram of Fig. 6 has been desi nated 22 Fig. 1 and. consists oi the relatively movable contacts 38 and 39, the contact 38 being controlled by means of a member 41 which is pivotally mounted to the shaft 42. One end of member 41 is provided with a projection 43 which is adapted to be normally urged into contact with the periphery of the selector wheel 33, as by means 0'1 a weight 44 attached to arm 41. After the selector wheel 33 has been rotated a given amount, the. projection 43 is adapted to drop into a notch 46 and thereby permit suiiicient movement of arm 41 to close the contacts 38 and 39.

The switch designated as 13 in Fig. 6, has been designated 23' in Fig. 1 and comprises the relatively movable contacts 47 and 48. Normally these contacts remain closed but upon the reception or" a series or" selecting impulses, they are moved apart and remain so until the reception of a long ringing impulse, during which they close to cause the ringing current to pass thru the telephone ringers. This control over the contacts 47 and 43 is etiected by means of a device which is set in motion at the beginning. of the first selecting impulse and which moves sufficiently slow that it does not effect closing of the contacts betore the beginning of a succeeding selecting impulse. A suitable mechanism which has been shown in the drawing consists of a bellows 51 which is biased towards closed position as by means of a weight 52, and which has provision for restricted escape of air so that when the bellows moved. to open position, it will return relatively slowly'to closed position. One of the contacts of switch 23, say contact 48 is mounted upon the movable portion 53 of this bellows- For moving the bellows 51 to open position responsive to the reception of a selecting impulse, I have provided an arm 54 adapted to be actuated by reciprocation of the rod 27, and which is operatively connected to the moyable portion 53 of the bellows as by means of an arm56 having a pin and slot connection 57 with the movable portion 53.

For engaging the upper end of arm 54, there is provided an escapemeut member 53 which is pivotally mounted to the rod 27 as at59. An extension of rodv 27 is provided with a cam surface 61 adapted to ride upon the fixed member 62. \Vhen the selector magnets 24 are energized to actuate the armature 26, movement of rod 27 first carries with it the arm 54 by virtue oi the escapcmcut member 58, but near the. end of movement of arm 27, engagement oi? cam surface (51 with the fixed member 62 effects disengagement of the escapemcnt from arm 51, and thus permits this arm to slowly return to initial position together with the bellows 51. Fixed to the rod 27 there is also a detent (33 which is adapted to engage the arm 54 when the armai urc :36 is in closed position. The function of this detcut will be later explained, altho it may be mentionod at this time that it serves to prevent complete closing of the bellows 51.

After a ringing operation has been eil'ecled it is desirable to automatically provide for a release of the selector wheel 33 so that this wheel may return to initial position. For this purpose 1 have shown a link 66 having a pin andslot 67 with the arm 41, and pivotally connected at its lower end to one arm of a lever 68, this lever being suitably journaled upon a pin 69. The other a rm of lever 8 is adapted to he engaged by a member 71 which is carried by movable portion 53 of bellows 51. W'hcn the detent 63 is engaged with the arm 54 with armature 26 in closed position, switch 23 may be closed, but the bellows 51 cannot close sulliciently far to actuate link 66 to lift the projection 43 from the selector notch 46. However when the armature 26 is released as at the end of a ringing impulse, the bellows may close an additional amount which is sufficient to lift link 60 and arm 41, and thus dis engage the projection 43 from notch 46,1110!- by permit ting the selector wheel to rotate in a clockwise direction and return to its initial position.

In order to fully explain the operation of the device, it will be presumed that this particular apparatus has been constructed so that it will respond to a code consisting of two relatively short impulses of pulsating ringing current which may be termed selecting impulses, followed by a relatively long impulse of pulsating current, which may be termed the ringing impulse. Before any impulses have been received, the parts of the apparatus will be substantially as shown in Fig. 1 with switch 22 open and switch 23 closed. Upon the reception of the first sclecting impulse, armature 26 is closed to ac.- tuate rod 27, and pawl 29 is engaged over a tooth of the notched wheel 31. Movement of rod 27 carries with it the arm 54 until the escapement member 58 is released by virtue of engagement of cam surface 61 with the stationary member 62. Movement of the arm 54 ill) lie

has caused opening of the bellows 51 and switch 23, and after release of arm 54 the bellows returns slowly toward closed position. This position of the apparatus with the armature closed during the first selecting inn pulse and after the release of arm Ciel, shown in Fig. 2. At the end of the first selecting impulse the armature 26 and rod return to original position and movement of the pawl 29 carries with it the notched wheel 31 and the selector wheel 33. The friction between the projection 43 and the periphery of the selector wheel 33 is sufficient to overcome the tension of spring 341-, so that the selector wheel will remain in this new position after release of pawl 29. The next select ing impulse begins shortly after the termination of the first impulse, and has been shown in Fig. 41, the armature 26 is again moved to closed position to cause pawl 29 to engage a new tooth of the wheel 31. Likewise the bellows 51 is again moved to open position as has previously been described with respect to the first selecting impulse. At the end of this second selecting impulse the selector wheel 33 is rotated to bring the notch l6 in position to be engaged by the pro jection l and movement of arm il causes closing of the contacts of switch 22.. The last part of the second selecting impulse liowever does not cause energizatirm of the ring ing magnets as the bellows 51 keeps the switch 23 open until after the starting of the third long impulse or ringing impulse. At the beginning of the final long ringing impulse, armature 26 is again closed and causes the arm 1- to be tripped. The bellows 51 then closes sufficiently far to permit closing of the contacts of switch at which time the arm 5% comes in contact with the detent member 63. Switch is therefore closed during a part of the time that the long ringing impulse is being transmitted over the line, and again referring to the diagram of Fig 6, it will be seen that the closure of both of these switches fauses the current to divide and to BLISS thru the ringing nnignets of the telephone. Thus the last part of the ringing impulse causing ringing of the telephone after closure of switch 23.

After the last long impulse has ceased, the armature 26 returns to open position as shown in Fig. 6. The detent 63 is thus removed from arm 54iso that bellows 51 is permitted to close farther than it has during any part of the selecting or ringing operation. This farther closing of the bellows causes member 71 to engage the lever 68 and. thus lift the link (56 to lift the arm 41 from the notch 46, thus per mitting the selector wheel 33 to rotate under the tension of spring 34. and return to initial position. The apparatus is now ready to receive a new code combination.

Vi iththe apparatus as described above, the last long impulse will effect ringing of a bell of a subscribers telephone which is equipped with an apparatus which causes closing of both the switch 12 and 13 when two preceding short selecting impulses are received. If along ringing impulse preceded only by a short selecting impulse, then the projection 43 will not drop into the notch 46 and switch 22 will not be closed during the ringing impulse. Likewise if a combination is received having three selecting im pulses preceding the long ringing impulse, then the selector wheel 33 will be moved to a position which will cause projection 13 to ride out of the notch 46 and thus keep the switch 22 open during the ringing impulse.

In practice a number of subscriber tele phones are equipped. with apparatus as described above. The only difference in the individual apparatus is that the notches 46 in the selecting wheels are arranged at diilerent points about the periphery thereof so that a different numbe' of selecting impulses will be required to effect energization of the respective ringing magnets during the long ringing impulse. Assuming that there are four stations which are adapted to be rung separately, referring to Fig. 3, the first station may respond to a single long ringing impulse. Similarly stations B, C, and D may respond respectively to one short selecting impulse followed by a long ringing impulse, to two short selecting impulses, and to three short selecting in'ipulses followed by the ringing impulse. Code signals of this kind correspond to the signals at present in use in tele phone centrals for ringing different subscribers.

In order to provide for uniformity of installations, preferably all of the subscribers have a selecting apparatus of similar structure. These individual appa atuses are preferably adj ustable, as by having the notch ac adjustable with respect to the selector wheel, so that they may be set to respond to given code combination. The sub scrioc station which responus to a single long ringing impulse, preferably has its apparatus equipped with an auxiliary switch 123. The contacts of this switch are arranged to be closed only after the lapse of a substantial time following energization of magnets 24;. The contacts of this switch are then substituted in placeof the contacts of switch 23, in the circuit diagram as shown in Fig. 6. The selector wheel for this first station has its notch 46 arranged in such a position that normally it is engaged by member 43. Vlhen a single long impulse is transmitted over the line, magnets 24 are energized and cause switch 123 to be opened to prevent immediate ringing. However during the latter part of the long impulse, switch 123 is closed, and together vith closed switch 22, closes the circuit thru ringer 10. When another code combination is received, say one lll) " selecting mechanism.

having two short selecting impulses followed by a long ringing impulse, the first short selecting iinpulse will not be sufficiently long to permit closing of switch 123 and thus other code combinations cannot effect ringing. of

' this first station. 7

selector magnet 24 will not efifect further rotation of the selector wheel.

It is tobe particularly noted that in this system the present alternating or pulsating ringing current of telephone systems is used both to select the desired station and to supply the current to actuate the telephone ringer magnets, and that no local batteries or other source of. electrical energy are required. Furthermore the apparatus may be readily incorporated with existing telephone systems without making any elaborate alterations. Similar code combinations are at present being employed on party telephone lines although at present no selecting mechanism is being utilized. \Vith: this system practically the same code combinations may be employed to operate the selecting apparatus and thus prevent ringing the bells of all telephones except that of the subscriber desired.

I claim:

1. In a. telephone signaling system, a plurality of receiving stations connected to a common telephone line, each of said stations having ringing means adapted to be actuated by pulsating current, and at least two of said sta tic-ns being provided. with selecting switchmeans for operatively connecting said ringin means to the telephone line only after a long pulsating current impulse has been preceded by a definite number of short impulses, and means for etlecting automatic resetting of said switching means after the termination of said long impulse, said means beingautomatically conditionedupon the termination of said long impulse.

2. In a signaling system, a signal circuit, a response circuit, a pair of switches adapted to be closed for connecting the response circuit to the signal circuit, each switch havingrelatlVGlYIHOViLblG contacts, a selecting magnet connected" to said signal circuit, selector meansa-dapted to be moved by said magnet to efieet closing of one switch after the magnet has been energized by a definite number of selecting impulses, means for normally biasing the contacts of the other switch toward closed position, means'serving to move said latter contacts apart upon the reception of each selector impulse, means for retarding closing oi the contacts 015 said other switch before the next selecting impulse is received.

3. In a, signaling system adapted to effect signaling at a remote station in response to a signal code consisting of a definite number of snort spaced selecting impulses followed by a long signal impulse, said system includ ng a response circuit located at the reccix station, a pair oi switches adapted tobe closed for connecting the response circuit to the signal circuit, each switch having relatively movable contacts, a selecting magnet connected tothe signal circuit, a selector member adapted to be moved by said magnet in response to each selecting impulse for ell'ecting closing of one switch while the signal impulse is being received, means or normally biasing the contacts of the other switch toward closed position, means serving to move the contacts of said other switch apart upon. the reccption ct each selector impulse, and means for retarding closing of the contacts oi said other switch before the next selector impulse is received but permitting closing during reception of the long signal impulse.

4. 111 a signaling system adapted to cllect signaling at a remote station in rcsyxmse to a signal code consisting of a definite number of short spaced selecting impulses followed by a long signal impulse, said system including a response circuit located at the receiving station, a pair of switches adapted to be closed for connecting the response circuit to the signal circuit, each switch having relatively movable contacts, a selecting magnet connected to the signal circuit, a selector member adapted to be moved by said magnet in response to each selecting impulse for effecting closing of one switch while the signal impulse is being. received, means for normally biasing the contacts of the other switch toward closed position, means serving to move the contacts of said other switch apart upon the reception of each selector impulse, means for retarding closing 01" the contacts of said other switch before the next selector impulse is received, and means for efl'ectin g return of said selector member to initial position upon the cessation of the signal impulse.

5. In a. signaling system adapted to effect signaling at a remote station in response to a signal code consisting of a definite number of short spaced selecting impulses followed by a longsignal impulse, said system including a response circuit located at the receiving station, a pair of switches adapted to be closed for connecting the response circuit to the signal circuit, each switch having relatively movable contacts a selecting magnet connected to the signal. circuit, a selector member adapted to be moved by said magnet in response to each selecting impulse for effecting closing of one switch while the signal impulse is being received, means adapted to be tripped upon energization of the selector magnet for effecting movement of the contacts of said llfi other switch apart, means for effecting closing of said contacts after a period of time which is greater than the lapse of time between the beginning of each selector impulse.

6. In a telephone ringing system, adapted to selectively ring the bell of a telephone in response to a signal code consisting oi a definite number of short spaced selecting inipulses folio wed by a long ringing impulse, said system including a ringing circuit, a pair ot switches adapted to be closed for connecting the ringing circuit to the telephone lines, each switch having relatively movable contacts, aselecting magnet connected to the telephone lines, a selector wheel adapted to be rotated by said magnet in response to each signal impulse for effecting closing of one switch While the ringing impulse is being received, means adapted to be actuated upon energization of said magnet for effecting closing of the contacts after a period of time which is greater than the period between the beginning 01' each impulse whereby said one switch is not closed until during reception oi the long ringing impulse, and means for effecting automatic return of the selector Wheel to initial position after cessation of the long ringing impulse.

In testimony whereof, I have hereunto set my hand.

FRED A. BENNETT. 

